Philippine Birds of Prey

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The Endemic Raptors of the Philippines An Illustrated Guide



TABLE OF CONTENTS Introduction 12 Raptor Facts 14 Endemic Raptors 39 Philippine Eagle 42 Philippine Hawk Eagle 46 Philippine Serpent Eagle 48 Philippine Honey Buzzard 52 Philippine Falconet 56 Philippine Eagle Owl 62 Philippine Scops Owl 63 Philippine Hawk Owl 83 Conservation Efforts 102

INTRODUCTION The Philippines is considered one of the by their conservative life strategy. None- 17 megadiverse countries in the world, theless, they have attracted an interest containing atleast two-thirds of earth’s from the point of view of con- biodiversity and a high population of servation biology because fauna and flora species. Birds, especial- many populations have ly raptors, play an important role in the been close to extinction. ecosystems. They are referred to as in- Hence, it is vital to cre- dicator species because threats like hab- ate a national agen- itat loss and climate change have the da for these species. most dramatic impact on top predators. Birds, especially raptors, play an impor- tant role in ecosystems. They are referred to as indicator species because threats like habitat loss and climate change have the most dramatic impact on top pred- ators. They also play an important eco- logical role by controlling populations of rodents and other small mammals thus,creatingawell-balancedecosystem. In comparison with other avian species, raptors are an uncommon study model, mainly due to the limitations imposed 12

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RAPTORS Raptors and their development Raptors have frequent- The word raptor is de- Many birds hunt, kill, ly been defined on the rived from “rapere,” and eat meat, but they basis of diet or preda- a Latin word which may not be raptors. tory ecology. In fact, means to seize or cap- There are three distin- the term “raptor” has ture. More specifical- been applied to a fairly ly, a raptor is a bird of guishing traits that broad range of animals prey. A bird of prey is a including extinct feath- carnivore (meat eater) make raptors differ- ered dinosaurs in the that kills and eats mam- ent from other birds: Family Dromaeosau- mals, reptiles, amphib- -hooked beaks with ridae, which includes ians, insects, rodents sharp edges recognizable genera as well as other birds. -feet with sharp, curved such as Velociraptor. claws or talons -keen eyesight 14

Raptors are sexually dimorphic, mean- hunters than males. Their superior ing female and male birds differ in strength and hunting ability make size. Females are up to a third larg- them preferred birds for use in falcon- er than males. Because of their larg- ry best of their structure and function. er size, females are more aggressive 15

STRUCTURE OF RAPTORS Raptors have special characteristics and adaptations for hunting that set them apart from other birds. They primarily rely on flight for survival and their skeleton, feath- ers, skin and flight muscles make up about 60 percent of the pay- load. The contribution of each part of the body toward survival is bal- anced against the cost of carrying it. The skeleton is totally adapted for flight. Many of their bones are fused together, and they have a pronounced keel where the pec- toral muscles, that are responsible for wing movement, are attached. 16

In most raptors, males and females have very similar plumage. The most common way of distinguish- ing males and females in raptors is by size; the female being usual- ly bigger than the male. Therefore, plumage colour does not play a role when selecting a mate (partner). 17

Size One explanation for the females’ larger size suggests that it protects them from ag- 18 gressive males that are well equipped with sharp talons and beaks, and the killer in- stincts to go with them. Over evolutionary time, females have preferred to mate with smaller, safer males -- in fact, the female may have to be able to dominate the male for proper pair bonding to occur and for the male to remain in his key role as food provider to both female and young. Such a system would involve sexual selection for smaller size in males. Bird-hunting raptors are assumed to show aggression most suddenly, and to represent the great- est threat to their mates, and they are the ones exhibiting the greatest size difference.

Eyesight Birds of prey have very highly touch each other inside the skull. wide, and is especially concen- developed vision. Possessing They can see more colours trated in the front. Compared more rods and cones than other and can perceive objects to other birds like pigeons, vertebrates, provides them with about three times farther whose eyes are on the sides of advanced visual acuity and their away than humans can. But the head, the eyes of birds of retina is one and a half times their vision at night is weak. prey are situated in the front of thicker. The eyes of a raptor are Their field of vision is also very the head. This provides them very big. Taking up 2/3 of the with a binocular vision that space in their skull, they almost is well adapted for hunting. 19

Beak & Talon The shape of a bird’s beak is adapt- ed to its diet. Birds of prey have a hooked beak, curved with very sharp edges. Their beak is not used to catch their prey but to cut through flesh and tear off meat. It is used to kill by biting at the base of the prey’s neck. It is strong enough to rip off the carcass during feeding. 20

Raptors use their feet to capture their prey. They have thick scales to protect their feet from injury and strong toes that terminate in strongly curved triangular talons. Raptors have powerful leg and toe muscles that end with sharp tal- ons, making their feet lethal weap- ons which are perfectly designed to catch, hold, and carry prey. Talons are different from claws because they are often used for carrying prey. 21

Flight Like all birds, raptors use their strong breast muscles to flap their wings and give them the thrust to move through the air and fly. In a way, birds use a swim- ming motion to get the lift needed to fly. Plane wings have a similar shape as bird wings, but instead of flapping their wings, we use engines to thrust them into the air and create the lift needed to fly. 22

Feathers are without hooks located on the Feathers a doubt the most well barbules. Barbules, pro- known characteristic of jections that join barbs 23 birds. No other group together, each have lit- of living animals has tle hooks that allow the feathers. An incredible barbs of the feather to structure, the feather hook up to one another. allows birds to fly, keep warm or cool down, can be used in courtship displays during breed- ing season, and are then essential for keeping eggs and young warm. Barbs, the many tiny branches coming off the rachis (grooved tube- like structure at centre of the feather), create a feather surface (vanes) that stays together like Velcro, because of tiny

Eggs and Nest Usually, raptors nest in isolated vides food for the female which birds. Non-nesting birds are couples and depend on a hunt- must be fit for laying, incubat- usually young adult birds, with- ing territory that can range from ing and protecting the young. out their adult plumage, and 1 to over 300 square kilometres. Birds that find a mate and nest are not ready to assume the role The nest site is usually select- are called nesting birds or nest- of a parent yet. It can also hap- ed by the female and the nest is ers, whereas other birds which pen that adults that have not built by the two partners. After- do not are called non-nesting found a partner or a territo- wards, the male hunts and pro- ry are considered non-nesting. 24

Many birds have a tendency to come back to nest at the same place that they were born. This also means that the ar- eas used by certain species are well es- tablished. Large raptors usually nest in tall trees or on cliff ledges, and may use branches or leaves as nesting material. Once the nest is built, materials are added on year after year. If the cou- ple does not come back the following year, the nest will probably be used by another couple of the same species or by a different animal. Some nests can grow to very large sizes; the record for the largest Bald Eagle nest is 8 square metres, representing 100 years of effort. Raptors also nest on the ground or in burrows, in tree hollows, in nest boxes, in abandoned nests, on buildings and other human structures like the pylons of high-tension wires. 25

Food 26

Different types of birds of prey eat a wide range of different animals. In general, the larger the hunter the larger the prey, but many medium and large raptors will also choose easier, smaller meals, especially when small prey is more abundant. Large Insects: Grasshoppers, praying mantises, beetles, and other large in- sects are the preferred prey of small raptors such as American kestrels, merlins, and Mississippi kites. Raptors that spend a large amount of time on the ground, such as burrowing owls, also eat a lot of insects. 27

Amphibians: Smaller birds of prey and those that prefer habitats near water often feed on amphibians such as frogs, toads, and salaman- ders. Red-shouldered hawks and American kestrels often include amphibians in their diet. Reptiles: Snakes and lizards are popular prey for desert-dwelling raptors such as the crested caracara. The barred owl is also known to feed frequently on reptiles. 28

Small Mammals: Small mammals such as mice, voles, shrews, and gophers are the most popular prey for medium and large raptors. Red-tailed hawks, northern harriers, Coop- er’s hawks, barn owls, merlins, and many other species hunt small mammals, either by perching and scanning fields or by soaring to spot prey. Small Birds: Many small birds including finches, sparrows, and songbirds are prey for larger birds. Depending on the raptor species, they may surprise smaller birds on the ground or catch them in mid- flight, either through diving or after an acrobatic aerial chase. Accipiters such as sharp-shinned hawks and Cooper’s hawks are specialists at hunting small birds. 29

Large Birds: Larger birds such as pigeons, doves, ducks, rails, and grouse often become prey for larg- er raptors. Fierce predators such as the northern goshawk and the swift diving peregrine falcon feed frequently on larger birds. Medium Mammals: Medium-sized mammals such as rabbits, raccoons, and large squirrels are regular parts of the diet of large birds of prey. Red- tailed hawks, ferruginous hawks, northern goshawks, and golden ea- gles hunt these bigger mammals. 30

Fish: Birds of prey that live along coast- Carrion: Dead animals and rotting carcass- lines or near large bodies of water often es are the primary diet of scavenging raptors hunt fish, in some cases poaching it from such as the turkey vulture and the Califor- other predators such as bears, raccoons, nia condor. Other large raptors, including and mountain lions. Fish is the majority of golden and bald eagles, will also choose the diet for bald eagles and osprey, and the an easy meal like carrion if it is available. snowy owl will also occasionally eat fish. 31

Habitat They can be found in al- largely on food availability. range size is large. Differ- pine areas down to de- In general, if prey is abun- ences in home range size not serts, grasslands, for- dant near the nest, home only exist between species, ests, and human suburbs. range size is small. If prey but within the same species. Home range size during the is scarce or far away, home breeding season depends 32

Conservation Throughout the world, odiversity could dis- ent sectors of socie- economic returns ei- raptor populations rupt critical ecosys- ty that have opposing ther from habitats on have declined and tem services and affect views about priorities. which raptors depend, species have become human well-being. Thus there are con- the prey which raptors threatened as a re- Consequently, these flicts between those eat, or indeed from sult of human activity activities often bring who may be more con- exploitation for the such that losses of bi- into conflict differ- cerned with deriving raptors themselves. 33

Threats The largest and most fragmented either as a the overall availability of tensification of agricul- challenging conflicts result of exploitation or given habitats is not an ture, such as increased concerning raptor con- those natural resourc- issue, the way those habi- use of pesticides, has had servation arise over land es or to make way for tats are managed also has and still has a significant use. The natural habitats alternate forms of land an influence on raptors. impact on many raptors. continue to be lost and such as agriculture when Examples of these are in- 34

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The tools of a naturalist Naturalists use many day that the naturalist nature that is new to teries in the natural tools in studying na- continue to document you. Writing down world and sometimes ture, such as binoc- what they see and how every detail that you great discoveries are ulars, cameras, tape they see it. Keeping a can think of so that made by the amateur recorders, rulers, journal is a good way you can recall it at a naturalist who is prac- tweezers, and most to jog your memory later date for compari- ticed at journaling. important, journals. when you come across son or research. There It is still important to- a species or event in remain many mys- 36

“In every walk with nature one receives far more than he seeks.” -John Muir 37



Endemic Raptors of the Philippines 39



Accipitridae Family A large family of carnivorous birds having comparatively rounded wings, long legs, and an unnotched bill and including the typical hawks and goshawks, the kites, and usually the eagles Accipiters are fierce, stealthy hunters and their diet consists mostly of other birds and small mammals. 41

Philippine Eagle CRITICALLY ENDANGERED Pithecophaga jefferyi The Great Philippine Eagle, also known as the “Haribon Eagle” is one of the largest eagles, and continues to be one of the most endangered birds of prey in the world. Description: an adult eagle has a dark face and a creamy-brown nape and crown; huge, broad rounded wings and long tail; massive arched blu- ish-gray bill; blue-grey eyes; underparts with dark brown shaft streaks; tail above and flight feathers are dark brown with black bars; and, heavy legs are yellow, with large, powerful, dark claws. Habits: often found in lowland montane forests Range: Leyte, eastern Luzon, Mindanao, and Samar Diet: monkeys, bats, civets, flying squirrels, ma- caques and other birds of prey, snakes and lizards Population: 180-500 Threats: deforestation and wildlife poaching Conservation Action: The species occurs in sev- eral protected areas including the Northern Sierra Madre Natural Park on Luzon, Mt Kitanglad and Mt Apo Natural Parks on Mindanao. 42

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Female eagles usually lay one egg every two Juveniles stay with their parents until they’re years, which they incubate for almost two about a year and a half old. Then, for the next months, with some assistance from their four years, they strike out on their own, wan- partners. After the chick hatches, the male dering from forest to forest and crossing open eagle initially does most of the hunting while fields until they reach sexual maturity, when the mother does most of the feeding. they find a mate and a place to settle down 44

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Northern Philippine hawk-eagle ENDANGERED Nisaetus philippensis Description: with a crest on top of its head, feath- ered tarsus, booted legs; adults: top of the head, nape, and face feathers basal half buff with half distal dark brown; throat buff with dark brown mesial stripe and distinct streaked moustachial stripes Habits: uncommon in forests from the lowlands Range: Luzon and Mindoro Diet: Prey not recorded Population: 400-600 Threats: habitat loss in the form of logging and agriculture Conservation Action: It has been recorded in numerous protected areas, including Mts Isarog and Makiling National Parks, the Northern Sier- ra Madre Natural Park and Bataan Natural Park/ Subic Bay and recently on Mount Irid-Angelo-Bi- nuang of the Southern Sierra Madre in Luzon, as well as Tadao Ilocos Norte, Mt Palay Palay and Mt Banahaw. 46

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Southern Philippine hawk-eagle ENDANGERED Nisaetus pinskeri Description: pale-colored to white along the head and crown, with black streaking along the white-buff breast. There is narrow white and rufous barring on the belly and black barring on the thighs and cris- sum. The wings are barred black and brown. Juve- niles have barred thighs Habits: found in tropical moist highland forests Range: Mindanao, Negros, and Samar Diet: Prey not recorded, but probably feeds on birds. Population: 600-800 Threats: habitat loss in the form of logging and agri- culture Conservation Action: Recorded from numerous protected areas, including Mt Canlaon on Negros, Mt Kitanglad and Mt Apo Natural Parks and Mt Ma- lindang on Mindanao, and Rajah Sikatuna National Park on Bohol. 48

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Philippine serpent eagle LEAST CONCERN Spilornis holospilus Description: The philippine serpent eagle color is brown from above and it has a short bushy chest, black crown and gray-brown cheeks and throat. The under- parts are rufous with white spots, while its tail is black with a white tip, light-brown central band and a sec- ondary basal band. The primary feathers are also black and have white spotting along the wing coverts. The eyes, legs and lores are yellow. Habits: occupies habitat with over 50% canopy cover and hunts above the forest Range: Luzon and Mindanao Diet: snakes and lizards Population: unknown Threats: habitat destruction, Conservation: IBA - Zambales Mountains 50